Liquid-crystalline medium

Abstract

The invention relates to a liquid crystalline medium, characterised in that it comprises one or more compounds of formula A ##STR00001##
and
one or more compounds of formula II ##STR00002##
wherein the parameters have the meaning indicated in claim 1, and to high-frequency components comprising the same, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, in particular microwave phased-array antennas.

Claims

1. A liquid-crystal medium, comprising one or more compounds of formula A-2 ##STR00274## wherein R.sup.01 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, and X.sup.01 denotes F, Cl, NCS, SF.sub.5, fluorinated alkyl, fluorinated alkenyl or fluorinated alkoxy having 1 to 7 C atoms; and one or more compounds of formula II ##STR00275## wherein L.sup.21 denotes R.sup.21 and, in the case where Z.sup.21 and/or Z.sup.22 denote trans-CHCH or trans-CFCF, alternatively denotes X.sup.21, L.sup.22 denotes R.sup.22 and, in the case where Z.sup.21 and/or Z.sup.22 denote trans-CHCH or trans-CFCF, alternatively denotes X.sup.22, R.sup.21 and R.sup.22 independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.21 and X.sup.22 independently of one another, denote F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or alkoxy having 1 to 7 C atoms or fluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms, or NCS, Z.sup.21 and Z.sup.22 denotes trans-CHCH, trans-CFCF, CC or a single bond, with the proviso that at least one of Z.sup.21 and Z.sup.22 denotes CC, ##STR00276## to ##STR00277## independently of one another, denote ##STR00278## and n denotes 0 or 1.

2. The liquid-crystal medium according to claim 1, additionally comprising one or more compounds of the formula I ##STR00279## wherein L.sup.11 denotes R.sup.11 or X.sup.11, L.sup.12 denotes R.sup.12 or X.sup.12, R.sup.11 and R.sup.12 independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.11 and X.sup.12 independently of one another, denote H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, unfluorinated or fluorinated alkenyloxy or unfluorinated or fluorinated alkoxyalkyl having 2 to 7 C atoms, and ##STR00280## to ##STR00281## independently of one another, denote ##STR00282##

3. The liquid-crystal medium according to claim 2, wherein one or more compounds of formula I are of formula I-1c ##STR00283## wherein Y.sup.11 and Y.sup.12 independently of one another, denote H or F, R.sup.11 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, and X.sup.12 denotes F, Cl or OCF.sub.3.

4. The liquid-crystal medium according to claim 1, wherein one or more compounds of formula II are of one or more compounds of formulae II-1 to II-6: ##STR00284## in which Z.sup.21 and Z.sup.22 denote trans-CHCH or trans-CFCF, R.sup.21 and R.sup.22 independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkynyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.22 denotes F, Cl, CN or NCS, and and one of ##STR00285## to ##STR00286## denotes ##STR00287## and the others independently of each other denote ##STR00288## and where the compounds of formula II-3 are excluded from the compounds of formula II-2.

5. The liquid-crystal medium according to claim 1, wherein the total concentration of the one or more compounds of formula A-2 in the medium is 1% to 30%.

6. The liquid-crystal medium according to claim 1, wherein, in formula A-2, R.sup.01 denotes unfluorinated alkyl with 1 to 6 C atoms and X.sup.01 denotes F.

7. The liquid-crystal medium according to claim 1, wherein the total concentration of the one or more compounds of the formula II in the medium is 30% to 99%.

8. A component for high-frequency technology, comprising the liquid crystal medium according to claim 1.

9. The component according to claim 8, which is suitable for operation in the microwave range.

10. The component according to claim 8, which is a phase shifter.

11. A process for preparing the liquid-crystal medium according to claim 1, comprising mixing one or more compounds of formula A-2 with one or more compounds of formula II, and optionally with one or more further compounds and/or with one or more additives.

12. A microwave antenna array, comprising one or more components according to claim 8.

13. A compound of formula A-2 ##STR00289## wherein R.sup.01 denotes H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, and X.sup.01 denotes F, Cl, NCS, SF.sub.5, fluorinated alkyl, fluorinated alkenyl or fluorinated alkoxy having 1 to 7 C atoms.

14. The compound according to claim 13, wherein X.sup.01 denotes F.

15. The compound according to claim 13, wherein one or more compounds of formula A-2 are of one or more compounds of formulae A-2a to A-2f ##STR00290##

16. The compound according to claim 15, wherein one or more compounds of formula A-2 are of one or more compounds of formulae A-2c to A-2f.

17. The liquid-crystal medium according to claim 1, wherein, in formula A-2, X.sup.01 denotes F.

18. The liquid-crystal medium according to claim 1, wherein, in formula A-2, X.sup.01 denotes unfluorinated alkyl with 3 to 6 C atoms and X.sup.01 denotes F.

19. The liquid-crystal medium according to claim 1, wherein the total concentration of the one or more compounds of formula A-2 in the medium is 5% to 20%.

20. The liquid-crystal medium according to claim 1, wherein the total concentration of the one or more compounds of formula A-2 in the medium is 10 to 15%.

Description

EXAMPLES

(1) The examples below illustrate the present invention without limiting it in any way.

(2) Synthesis

(3) 4-Alkylphenylacetylenes and 4-fluorophenylacetylene are known to the literature and were synthesised as described therein.

1. 1-(4-Butyl-phenylethynyl)-2,5-difluoro-4-(4-hexyl-phenylethynyl)benzene

1.1 1-Bromo-4-(4-ethyl-phenylethynyl)-2,5-difluoro-benzene and 1,4-Bis-(4-hexyl-phenylethynyl)-2,5-difluoro-benzene

(4) ##STR00269##

(5) To a mixture of 1,4-dibromo-2,5-difluorobenzene (101 g, 0.37 mol), bis(triphenylphosphine)palladium(II)chloride (15.0 g, 0.02 mol) and copper(I)iodid (2.0 g, 0.01 mol) in diisopropylamine (500 ml) a solution of 4-hexylphenylacetylene (CAS 79887-11-9, 93.2 g, 0.50 mol) in diisopropylamine (1.00 l) is added dropwise at 70 C. The reaction is stirred at room temp. overnight, filtered and the solvent is evaporated i. vac. The product mixture is separated by column chromatography with petrol ether on silica to give 1-bromo-4-(4-ethyl-phenylethynyl)-2,5-difluoro-benzene and 1,4-bis-(4-hexyl-phenylethynyl)-2,5-difluoro-benzene. The latter is recrystallised from petrol ether to give colourless crystals, m.p. 94 C.

1.2 1-(4-Butyl-phenylethynyl)-2,5-difluoro-4-(4-hexyl-phenylethynyl)benzene

(6) ##STR00270##

(7) To a mixture of 1-bromo-4-(4-ethyl-phenylethynyl)-2,5-difluoro-benzene (19.5 g, 45.5 mmol), bis(triphenylphosphin)palladium(II)chlorid (1.5 g, 2.0 mmol) and copper(I)iodid (0.2 g, 1.0 mmol) in diisopropylamine (50 ml) a solution of 4-butylphenylacetylene (9.0 g, 56.9 mmol) in diisopropylamine (100 ml) is added dropwise at 70 C. The reaction is stirred at room temp. overnight, filtered and the solvent is evaporated i. vac. The product is purified by column chromatography with petrol ether on silica and recrystallised from petrol ether to give 1-(4-butyl-phenylethynyl)-2,5-difluoro-4-(4-hexyl-phenylethynyl)-benzene as colourless crystals, m.p. 73 C.

2. 1-(4-Butyl-phenylethynyl)-2,5-difluoro-4-(4-fluoro-phenylethynyl)benzene

2.1 1-Bromo-2,5-difluoro-4-(4-fluoro-phenylethynyl)-benzene

(8) ##STR00271##

(9) To a mixture of 1,4-dibromo-2,5-difluorobenzene (171.3 g, 0.63 mol), bis(triphenylphosphin)palladium(II)chloride (11.7 g, 16.6 mmol) and copper(I)iodide (1.6 g, 8.3 mmol) in diisopropylamine (500 ml) a solution of 4-fluorophenylacetylene (50.0 g, 0.42 mol) in diisopropylamine (1000 ml) is added dropwise at 70 C. The reaction is stirred at room temp. overnight, filtered and the solvent is evaporated i. vac. The product is purified by column chromatography with petrol ether on silica and recrystallised from petrol ether to give 1-bromo-2,5-difluoro-4-(4-fluoro-phenylethynyl)benzene as colourless crystals.

2.2 1-(4-Butyl-phenylethynyl)-2,5-difluoro-4-(4-fluoro-phenylethynyl)benzene

(10) ##STR00272##

(11) To a mixture of 1-bromo-2,5-difluoro-4-(4-fluoro-phenylethynyl)-benzene (16.0 g, 45.0 mmol), bis(triphenylphosphin)palladium(II)chloride (1.5 g, 2.0 mmol) and copper(I)iodide (0.2 g, 1.0 mmol) in diisopropylamine (80 ml) a solution of 4-butylphenylacetylen (8.5 g, 54.0 mmol) in diisopropylamine (100 ml) is added dropwise at 70 C. The reaction is stirred at room temp. overnight, filtered and the solvent is evaporated i. vac. The product is purified by column chromatography with petrol ether on silica and recrystallised from petrol ether to give 1-(4-Ethyl-phenylethynyl)-2,5-difluoro-4-(4-fluoro-phenylethynyl)-benzene as colourless crystals, m.p. 99 C.

(12) The following table 1 shows the phase sequences of the examples 1 and 2 and of further compounds obtained in analogy to the above described syntheses.

(13) ##STR00273##

(14) TABLE-US-00007 TABLE 1 Example R.sup.01 L.sup.01 Phase (T/ C.) 1 C.sub.4H.sub.9 C.sub.6H.sub.13 K 73 N 157 I 2 C.sub.4H.sub.9 F K 99 N 162 I 3 C.sub.3H.sub.7 C.sub.6H.sub.13 K 67 N 169 I 4 C.sub.3H.sub.7 F K 105 N 179 I 5 C.sub.5H.sub.11 F K 109 N 163 I 6 C.sub.6H.sub.13 F K 108 N 150 I 7 C.sub.6H.sub.13 C.sub.6H.sub.13 K 94 N 149 I 8 C.sub.3H.sub.7 C.sub.3H.sub.7 K 153 N 199 I 9 C.sub.4H.sub.9 C.sub.4H.sub.9 K 100 N 167 I 10 C.sub.5H.sub.11 C.sub.5H.sub.11 K 87 N 172 I

MIXTURE EXAMPLES

(15) The examples are compared to reference mixtures from the state of the art that do not contain compounds of formula A of the present invention.

Examples 1.1 to 1.4

(16) The following reference mixture (RM-1) and Mixture examples M-1 to M-4 are prepared and investigated.

(17) TABLE-US-00008 Mixture RM-1 Composition Compound Concentration/ No. Abbreviation % by weight 1 CC-3-V 16.0 2 PP-1-2V1 6.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 38.0 5 GGP-5-CL 18.0 6 PGUQU-5-F 2.0 100.0 Physical properties T (N, I) = 123.0 C. n (20 C., 589 nm) = 0.2838 (20, 1 kHz) = 3.2 .sub.1 (20 C.) = 253 mPa .Math. s k.sub.11 (20 C.) = 17.5 pN k.sub.33 (20 C.) = 23.3 pN

(18) TABLE-US-00009 Mixture M-1 Composition Compound Concentration/ No. Abbreviation % by weight 1 CC-3-V 16.0 2 PP-1-2V1 6.0 3 PPTUI-3-2 15.0 4 PPTUI-3-4 28.0 5 GGP-5-CL 18.0 6 PGUQU-5-F 2.0 7 PTXTP-4-6 5.0 8 PTXTP-3-F 5.0 9 PTXTP-4-F 5.0 100.0 Physical properties T (N, I) = 122.0 C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 3.6 1 (20 C.) = 269 mPa .Math. s k.sub.11 (20 C.) = 16.8 pN k.sub.33 (20 C.) = 25.4 pN

(19) TABLE-US-00010 Mixture M-2 Composition Compound Concentration/ No. Abbreviation % by weight 1 CC-3-V 16.0 2 PP-1-2V1 6.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 30.0 5 GGP-3-CL 10.0 6 GGP-5-CL 8.0 7 PTXTP-4-6 10.0 100.0 Physical properties T (N, I) = 124.0 C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 2.7 .sub.1 (20 C.) = 297 mPa .Math. s k.sub.11 (20 C.) = 17.4 pN k.sub.33 (20 C.) = 26.4 pN

(20) TABLE-US-00011 Mixture M-3 Composition Compound Concentration/ No. Abbreviation % by weight 1 CC-3-V 10.0 2 PP-1-2V1 7.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 30.0 5 GGP-5-CL 20.0 6 PGUQU-5-F 3.0 7 PTXTP-4-6 10.0 100.0 Physical properties T (N, I) = 129.0 C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 4.0 .sub.1 (20 C.) = 331 mPa .Math. s k.sub.11 (20 C.) = 17.8 pN k.sub.33 (20 C.) = 24.7 pN

(21) TABLE-US-00012 Mixture M-4 Composition Compound Concentration/ No. Abbreviation % by weight 1 PPTUI-3-2 20.0 2 PPTUI-3-4 30.0 3 GGP-3-CL 20.0 4 PGUQU-5-F 3.0 5 PTXTP-4-6 10.0 6 PTP(1)I-4-A1 17.0 100.0 Physical properties T (N, I) = 129.5 C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 4.1 .sub.1 (20 C.) = 632 mPa .Math. s k.sub.11 (20 C.) = 14.7 pN k.sub.33 (20 C.) = 28.7 pN

(22) All mixtures M1 to M4 are very well suitable for applications in the microwave range, especially for phase shifters.

(23) In the following table 2, examples 1.4 to 1.4 are shown in comparison concerning tuneability (), dielectric loss (tan .sub..sub.r,) and material quality ().

(24) TABLE-US-00013 TABLE 2 Example Mixture tan .sub. r, (Ref.) RM-1 0.0125 0.2132 17.1 1.1 M-1 0.0126 0.2247 17.9 1.2 M-2 0.0125 0.2189 17.5 1.3 M-3 0.0129 0.2279 17.7 1.4 M-4 0.0127 0.2502 19.7

(25) The comparison shows improved material quality for all examples 1.1 to 1.4 due to improved tuneabilities with the same or only slightly larger dielectric losses.

Examples 2.1-2.2

(26) The following reference mixture (RM-2) and mixture examples M-5 and M-6 are prepared and investigated.

(27) TABLE-US-00014 Mixture RM-2 Composition Compound Concentration/ No. Abbreviation % by weight 1 PPTUI-3-2 10.0 2 PPTUI-3-4 15.0 2 PPTUI-4-4 30.0 3 PTP-3-5 14.0 4 PTP-4-5 14.0 5 PGUQU-3-F 2.0 6 PGUQU-5-F 3.0 7 CC-3-V 12.0 100.0 Physical properties T (N, I) = 97.5 C. n (20 C., 589 nm) = 0.2652 (20, 1 kHz) = 2.1 .sub.1 (20 C.) = 220 mPa .Math. s k.sub.11 (20 C.) = 13.5 pN k.sub.33 (20 C.) = 19.6 pN

(28) TABLE-US-00015 Mixture M-5 Composition Compound Concentration/ No. Abbreviation % by weight 1 PPTUI-3-2 10.0 2 PPTUI-3-4 10.0 2 PPTUI-4-4 30.0 3 PTP-3-5 11.0 4 PTP-4-5 11.0 5 PGUQU-3-F 3.0 6 PGUQU-5-F 3.0 7 CC-3-V 12.0 8 PTXTP-4-6 10.0 100.0 Physical properties T (N, I) = N/A C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 2.4 .sub.1 (20 C.) = 382 mPa .Math. s k.sub.11 (20 C.) = 14.4 pN k.sub.33 (20 C.) = 21.1 pN

(29) TABLE-US-00016 Mixture M-6 Composition Compound Concentration/ No. Abbreviation % by weight 1 PPTUI-3-2 10.0 2 PPTUI-3-4 10.0 2 PPTUI-4-4 30.0 3 PTP-3-5 11.0 4 PTP-4-5 11.0 5 PGUQU-3-F 2.0 6 PGUQU-5-F 2.0 7 PTXTP-4-6 10.0 8 PTP(1)I-4-A1 14.0 100.0 Physical properties T (N, I) = N/A C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 2.2 .sub.1 (20 C.) = 393 mPa .Math. s k.sub.11 (20 C.) = 11.5 pN k.sub.33 (20 C.) = 21.1 pN

(30) Both mixtures M5 and M6 are very well suitable for applications in the microwave range, especially for phase shifters.

(31) In the following table 2, examples 2.1. and 2.2 are shown in comparison with the reference RM-2 concerning tunability (t), dielectric loss (tan .sub..sub.r,) and material quality ().

(32) TABLE-US-00017 TABLE 2 Example Mixture tan .sub. r, (Ref.) RM-2 0.0103 0.2060 20.0 1.1 M-5 0.0102 0.2122 20.7 1.2 M-6 0.0088 0.2317 26.3

(33) The comparison shows improved material quality for both examples 2.1 and 2.2 due to improved tunabilities with lower dielectric losses.

Example 3.1

(34) The following reference mixture (RM-3) and Mixture examples M-7 are prepared and investigated.

(35) TABLE-US-00018 Mixture RM-3 Composition Compound Concentration/ No. Abbreviation % by weight 1 PTiNpTP-4-4 21.0 2 PTP(c3)TP-4-4 20.0 3 PTiNpTP-4-6 22.0 4 PTP(1)I-4-A1 30.0 5 PTiNpTP-6-6 7.0 100.0 Physical properties T (N, I) = N/A n (20 C., 589 nm) = N/A (20, 1 kHz) = 2.2 .sub.1 (20 C.) = 2136 mPa .Math. s k.sub.11 (20 C.) = 11.5 pN k.sub.33 (20 C.) = 21.1 pN tan .sub. r, = 0.0054 = 0.2654 = 48.9

(36) TABLE-US-00019 Mixture M-7 Composition Compound Concentration/ No. Abbreviation % by weight 1 PTiNpTP-4-4 21.0 2 PTiNpTP-4-6 22.0 3 PTP(1)I-4-A1 35.0 4 PTiNpTP-6-6 7.0 5 PTXTP-4-4 5.0 6 PTXTP-3-F 5.0 7 PTXTP-4-F 5.0 100.0 Physical properties T (N, I) = N/A C. n (20 C., 589 nm) = N/A (20, 1 kHz) = 1.3 .sub.1 (20 C.) = 1418 mPa .Math. s k.sub.11 (20 C.) = 11.4 pN k.sub.33 (20 C.) = 30.9 pN tan .sub. r, = 0.0058 = 0.278 = 48.1

(37) Mixtures M7 is very well suitable for applications in the microwave range, especially for phase shifters.

(38) The comparison of Mixture M-7 with Reference RM-3 shows similar properties in terms of material quality but at the same time a significantly reduced rotational viscosity.